Liland: Breaking his crown (in the terms you use) would make him neither richer nor poorer. A Crown was a 5 shilling piece(5*12 i.e. 60 old pence), and a half crown was 2 shillings and 6 pence (i.e.30 old pence).
4 crowns made 20 shillings, which was a pound.

Nigel